Background:Sodium arsenate (As), a toxic substance with induced oxidative stress, lead to hepatotoxicity. Olive oil (OO) with antioxidant property has protective effect on toxicity. The aim of this study was to investigate protective effect of OO on sodium As-induced hepatotoxicity in mice.Subjects and Methods:In this experimental study, 32 adult male BALB/c mice were divided randomly into four groups: control group (received only normal saline, the same volume as other groups), OO (0.4 mL/day, gavage), sodium As (15 mg/kg, gavage), and OO + sodium As (received OO 1 h before sodium As). Drugs were given for 30 consecutive days. After the last receipt of the drugs, oxidative stress parameters [malondialdehyde (MDA), glutathione (GSH)] in tissue, liver function parameters [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP)] in serum, ferric reducing ability of plasma (FRAP) in plasma, and histopathological assays were performed.Results:Sodium As induced hepatic injury as indicated by significant increase in AST, ALT, ALP, and LDH in serum and pathologic evidences. It also induces hepatic oxidative stress biomarkers as indicated by significant increase in levels of MDA and significant decrease in FRAP and GSH concentration. OO administration significantly improved oxidative stress parameters, histopathological changes, and enzymatic markers of liver injury.Conclusions:It was concluded that antioxidant activity of OO has hepatoprotective effect on As-induced hepatic injury.